LEWIS LH4 Brake Service Kit G2 for Lever and Caliper, X/a/a1/X0 Lever Mark

A marked LH4 lever is what this G2 kit is for, and the marks that count are X, a, a1 and X0. Split the parts into caliper and lever groups before you start, because the two ends use separate reference numbers.

Before you drain a marked LH4

Confirm two things in order: that the brake is an LH4, and that the lever shows X, a, a1 or X0. A lever with no mark uses the G1 kit instead. The kit notes also recommend consulting before purchase, so send a lever photo if there is any doubt about what you are reading.

Bench order for the LH4 caliper seals

Five rings belong to this end: two Caliper #5 piston O-rings, two Caliper #4 piston O-rings and one Caliper #14 clamshell O-ring. Their sizes are not given, so compare each old ring to its new partner as it comes out. Mixing the two piston references is the mistake to avoid.

Rebuilding the LH4 lever end

The lever parts are the piston, the modified sleeve made for LHT and LH4 only, two sleeve O-rings, front and rear piston O-rings, a spring, a circlip and a diaphragm. Two oil port O-rings, Lever #5, complete it. Note how the spring and piston sit before removing them, since general practice is to rebuild in reverse order.

• Lever marks named for G2: X, a, a1, X0
• Lever #15 piston and Lever #14 spring
• Lever #16 and #17 piston O-rings
• Lever #19 circlip and Lever #7 diaphragm
• No fluid or bleed tools on the parts list

Once both ends are back together you will still need a bleed with the correct fluid for your LH4, so line that up before the old seals come out of the brake.